The present invention relates to a new silver halide developing agent for color photographic materials, a composition of a processing solution containing the developing agent, and a method for forming a color image with the processing solution. In particular, the present invention relates to a developing agent for color photographic materials suitable for rapid processing of color photographs while keeping the processing solution from deterioration, a processing solution containing the developing agent, and a method for forming a color image with the processing solution.
As mini-labs for processing photosensitive materials within the shops and the amount of color negative films used in the field of news photos are increasing recently, the demand for completion of the development process in a shorter time to immediately provide the prints to the customers or to immediately place the photo in newspapers or the like is rapidly increasing. The demand for reduction of the processing time is becoming more and more eager in processing color negative films, since the time necessitated therefor is longer than that necessitated for processing color papers.
The reduction in the processing time is possible by changing the color developing agent in a color photographic photosensitive materials mainly comprising a silver bromoiodide emulsion such as color negative films. It was found that the processing time can be remarkably reduced by introducing a methoxy group into 2-position to form 4-(N-ethyl-N-.delta.-hydroxybutylamino)-2-methoxylaniline as described in Japanese Patent Unexamined Published Application (hereinafter referred to as "J. P. KOKAI") No. Hei 5-113635 or 4-(N-ethyl-N-.beta.-hydroxyethylamino)-2-methoxyaniline as described in J. P. KOKAI No. Sho 53-69035. It was also found that the processing time can be reduced with a developing agent having a water-soluble group-containing alkoxy group at the 2-position such as 2-(hydroxyethoxy)-4-diethylaminoaniline as described in U.S. Pat. No. 2,304,953.
However, it was found when a photosensitive material for color photography which mainly comprises a silver bromoiodide emulsion is developed with one of the compounds described in these specifications, a problem, i.e. a low resistance of the developer to oxidation with air, is caused. After testing the deterioration of various 4-(N,N-dialkylamino)-2-alkoxyanilines with time, it was found that the resistance to oxidation with air can be improved by replacing the group at the 2-position with isopropoxy group to form, for example, 4-[N,N-bis(.delta.-hydroxybutyl)amino]-2-isopropoxyaniline as described in J. P. KOKAI No. Hei 5-232654, or by replacing the group at the 2-position with t-butoxy group to form, for example, 4-(N-methyl-N-.gamma.-hydroxypropylamino)-2-t-butoxyaniline.
However, these two compounds described in J. P. KOKAI No. Hei 5-232654 capable of reducing the deterioration of the developer with time are yet unsatisfactory, since sufficient yellow density and cyan density are not easily obtained, though a high magenta density can be obtained.